Data geeks can find the underlying index data at the following S&P link:

April 2008 S&P Case Shiller HPI (XLS)

From Reuters:

Home prices extend record slide in April: S&P

NEW YORK (Reuters) - U.S. home prices extended their record slide in April, with every top metropolitan area now posting annual losses and many showing double-digit declines, according to the Standard & Poor’s/Case Shiller home price index report on Tuesday.

From Bloomberg:

S&P/Case-Shiller Home Prices Fell 15.3% in April, Index Shows

Home prices in 20 U.S. metropolitan areas fell in April by the most on record, signaling the housing recession is far from over, a private survey showed today.

The S&P/Case-Shiller home-price index dropped 15.3 percent from a year earlier, less than forecast, after a 14.3 percent decline in March. The gauge has fallen every month since January 2007. The group began keeping year-over-year records in 2001.

Mortgage defaults and foreclosures are adding to the glut of properties on the market, while stricter loan rules are making it more difficult for prospective buyers to get financing. The prolonged real-estate slump, along with higher fuel prices and a shrinking job market, is taking a toll on consumers and the economy.

“The weakness in prices is going to persist,” Ken Mayland, president of ClearView Economics LLC in Pepper Pike, Ohio, said before the report. “The mindset has yet to change. We’ll be looking at year-over-year declines in home prices well into 2009.”

Home prices decreased 1.4 percent in April from a month earlier after a 2.2 percent decline in March, the report showed. The figures aren’t adjusted for seasonal effects, so economists prefer to focus on year-over-year changes instead of month to month.

The index was forecast to fall 16 percent from a year earlier, after a previously reported 14.4 percent drop in the 12 months ended in March, according to the median forecast of 23 economists surveyed by Bloomberg News. Estimates ranged from declines of 15.4 percent to 17 percent.

From CNBC:

US Home Prices Continue Record Declines in April

U.S. home prices extended their record slide in April, with every top metropolitan area now posting annual losses and many showing double-digit declines, according to the Standard & Poor’s/Case Shiller home price index report.

The S&P/Case Shiller composite index of 20 metro areas fell 1.4 percent in April from March and slumped by a record 15.3 percent over the year.

Economists expected prices for the 20-city index to fall 2.0 percent in the month and 15.9 percent from April 2007, according to the median forecast in a Reuters survey.

S&P said its composite index of 10 metro areas slid 1.6 percent in April for a record 16.3 percent annual drop.

Home prices in a dozen of the metro areas have fallen for eight straight months.

From the WSJ:

Great Depression Home-Price Declines

The Standard & Poor’s/Case-Shiller home-price index, which reflects prices in 20 U.S. cities, is expected Tuesday to be reported down 16% in April from a year earlier, worse than March’s 14.4% decline.

“Most of the severe price declines are appearing now,” says Mark Zandi, of Moody’s Economy.com, who says house prices are down nationwide about 15% from their 2006 peak. With heavy inventory still to plow through, “I expect prices, when all is said and done, will be down about 25% this time next year,” he says. That skid off the peak would rank it on par with the Great Depression.

From Bloomberg:

U.S. Consumer Confidence in June Probably Fell to 15-Year Low

A report from S&P/Case-Shiller at 9 a.m. may show house prices in 20 U.S. metropolitan areas plunged 16 percent in April from a year earlier, the most since records began in 2001, according to the median estimate of economists surveyed. Forecasts ranged from declines of 15.4 percent to 17 percent.

From Forbes:

On the Watch: Home Prices

On Tuesday, two indexes measuring the change in home prices in April are likely to show declines, as a glut of unsold homes continues to pressure the struggling market.

The March Standard & Poor’s/Case-Shiller 20-city index showed home prices tumbling 14.4 percent in the month to the lowest level since the index was started in 2001.

Press release and datasets can be found at Standard & Poor’s:

S&P/Case-Shiller Home Price Indices